Every time we see a picture of singer John Legend with his supermodel wife, Chrissy Teigen, we remind ourselves that Legend used to work at Boston Consulting Group, where he made PowerPoint presentations. Just like one of us. Legend — who was still John Stephens when he lived in Boston — joined Teigen Tuesday night in New York at a party to celebrate the 50th anniversary of the Sports Illustrated swimsuit issue. She graces this year’s cover with model friends Nina Agdal and Lily Aldridge. It was announced this week that Grammy-winner Legend will be the graduation speaker at his alma matter, the University of Pennsylvania.Mark Shanahan can be reached at firstname.lastname@example.org. Follow him on Twitter @MarkAShanahan. Meredith Goldstein can be reached at email@example.com. Follow her on Twitter @MeredithGoldste.